Device for recirculating highly heated gases



J. S. MILLER DEVICE FOR REGIRULATIG HIGHLY HEATED GASES May 9,. 1933.

Filed NOV. 9, 1927 Patented May 9, 1933 UNITED STATES PATENT OFFICE .TAXES s. MILLER, OF wIoHTTA, xANs'AaAssIGNOR rro UmvERsAL OIL rnonuc'rs COMPANY, OF cmOAGO, ILLINOIS, A CORPORATION oEsoUTH DAKOTA DEVICE FOB RECIRCULATING HYIGHLYAEEATED GASES Application ined :member 0, 192'?,` serial No. 232,079.

The present improvements relate to a device adapted to cil culate and recirculate hot gases, and more particularly to a ldevice adapted to recirculate into a' furnace partlally or totally spent or used hot gasesof com-,

bustion.

Fans and blowers which are forms of d evices for accomplishing thls purpose, are in general use and are subjected to severe temperature conditions. Bearings and such other parts that would be damaged by heat,

must be kept out of vdirect contact wlth the hot gases that are being recirculated by the fan. In fans or blowers in use at the present time for the purpose specified, the bearings which support the shaft for rotating the fan( are located on only one side of the fan, tl 1e fan being carried on the free end of sald shaft and located within a housing or casing' and the Overhanging leverage caused by the inlet duct 2 and a gas discharge duct 3. i

fan bearing end of the shaft being unsupported, will often cause the shaft to warp or bend, thus causing the fan to wedge against or strike the housing, or be otherwise rendered inoperative.

The object of the present invention is to provide for bearings on both ends of the driving shaft. i. e., on both sides of the fan, to avoid the strain caused by the overhanging fan driving shaft, which bearings are mounted out of the path o f the hot gases to prevent them from being damaged.

The utility of the invention as well as other objects, features and advantages will be more particularly apparent from the following description.

The drawing is a side elevational view, partly in vertical section ofa device built according to the present invention.

In the drawing, 1 designates an indented.

metal housing or casing having a hot gas Plates 4 may be suitably mounted upon the housing 1 to support the mechanical assembly which may comprise a steam turbine 5 joined by means of a coupling 6 to the fan driving shaft 7 which may be driven by said turbine. Suitable bearings may be provided within the casings 8, 9 and l0 to support shaft 7.

Said casings may be adapted to accommodatel a liquid cooling medium such as water. The fan 11 may be mounted on shaft 7 and enclosed in the housing 1 in a position between the bearings retained in casings 9 and 10, which are located outside of thev housing 1.

In the operation of the apparatus, the spent gases from the furnace (not shown)l may be drawn through duct 2 by the fan 11 and forced through the discharge duct 3y into the combustion zone of the furnace (not shown). The temperature. of these gases may be rather high, sometimes reaching 2000 degrees F. more or less, depending `of course, upon the conditions of the operation wherein they are given off. Such high temperatures may cause the shaft 7 to become quite hot and conduct heat to the bearings supporting it which would, of course, cause damage to said bearings.

In order to cool the shaft and bearings, I

may provide boxes 12, 13, 14 and 15 which are suitably packed to retain a cooling liquid such as water and at the same time permit the shaft to rotate. Water or other cooling lnedia maybe introducedthrouo'h the pipe 16 controlled by valve 17 into the bearingretainingcasing 8, passing out of the latter through pipe 18 from which it/may flow into the bearing-retaining casing 9. From casing 9 the cooling liquid may pass through pipe 19 into the box 13 where it enters the revolving shaft 7, which contains a passageway of the conventional type to accommodate such cooling liquid and flows from said shaft into the boX `12 and out of the discharge pipe 2O controlled by valve 21. To cool that portion of the shaft on the opposite side of the fan, a similar structure may be employed. Water or other cooling media may be introduced into the bearing casing 10 j through pipe 22 controlled by valve 2??. Leaving the casing 10 through plpe 24 1t flows into the packed box 14 where 1t enters the shaft 7, which may contain a conventional passageway for cooling l1qu1ds, flowing out o'f said shaft into the box 15 from where it may be discharged through plpe 25 controlled by valve 26. l

It will be apparent from the above that I have perfected a device wherein there will occur a minimum of friction and a minimum of strain on the parts thereof. I have placed bearings on both sides of the fan or rotor, thus avoiding the wrenching effected upon bearings positioned on only one side of the fan. It Will be seen` that with my device the shaft is kept in perfect alignment, thus preventing the fan from wedging against the housing or casing surrounding it.

I claim as my invention:

1. A hot gas recirculating device comprising a housing, a rotatable shaft, a fan mounted on the shaft Within the housing, a bearing for the shaft exterior of the housing and having a jacket for cooling medium, a cooling box on the yshaft between the fan and the bearing, means for supplying cooling medium to the jacket, a passage connecting said box With the jacket, and a passage Within the shaft communicating with said box and having an outlet positioned to cause circulation of the cooling mediumthrough the shaft outside of the housing.

2. A hot gas recirculating device comprising in combination a housing, a rotatable shaft, a fan mounted upon said shaft and positioned Within said housing, a plurality of bearings for said shaft exteriorvof said housing, jackets for said bearings for a cooling medium,l cooling boxes on said shaft interposed between the bearings and the housing, means for circulating the cooling medium from the bearings to said boxes and means for circulating the cooling medium from said boxes through those portions of the shaft supported by the bearings.

3. A hot gas reeirculating device comprising in combination a housing, a rotatable shaft, a fan mounted upon said shaft and positioned within said housing, bearings for said shaft exterior and on opposite sides of said housing, jackets for said bearings for a cooling medium, cooling boxes for the shaft disposed upon said shaft on each side of each bearing, means for circulating the cooling medium from each of said bearings to a cooling box on one side of said bearing, and passages through said shaft connecting the boxes on each side of the shaft through which cooling medium may be passed.

let. A hot gas recirculating device comprising in combination a housing, a rotatable shaft, a fan mounted upon said shaft and positioned Within said housing, bearings for 

